A reaction system in which a particulate solid matter used as a catalyst or a heat medium is brought into contact with a reactant has conventionally been known. Some of the fluidized bed reactors functioning as this reaction system use a dense fluidized bed (bubble fluidized bed) or a high-speed moving bed (high-speed fluidized bed). The high-speed moving bed is used in a reaction that needs to reduce the time during which the solid particles are in contact with the gas (short contact time reaction). Nowadays, an upflow type high-speed moving bed reactor called “riser” has prevailed in fluid catalytic cracking units for producing gasoline using heavy oil or the like as stock oil. This is because the contact time was reduced as the catalytic performance improved, which enhanced the selectivity of the products including gasoline and prevented the occurrence of an unnecessary excessive decomposition reaction.
In the high-speed moving bed reactor, a mixture of a product gas and a particulate solid catalyst flows out of a reactor exit, and how the particulate solid catalyst can be separated promptly from the mixture is the critical issue of this type of device requiring a short contact time reaction. Therefore, the performance of the separator is very important.
The ones described in, for example, Patent Documents 1 to 3 are known as the above gas-solid separator.    Patent Document 1: Japanese Patent Application Publication No. H10-249122    Patent Document 2: U.S. Pat. No. 6,146,597    Patent Document 3: Japanese Patent Application Publication No. H10-249121